Volume No. 7 Issue No.: 4A Page No.: 1523-1530 April-June 2013

 

CLOSED RETTING : A GREEN TECHNOLOGY FOR CONTROLLING COIR RETTING POLLUTION OF BACKWATERS

 

Vardhanan Shibu Y.*1, Haridas Ajit and Manilal V.B. 2

1. Department of Zoology, University of Calicut, Malappuram, Kerala (INDIA)
2. National Institute for Interdisciplinary Science and Technology (CSIR), Thiruvananthapuram, Kerala (INDIA)

 

Received on : December 05, 2012

 

ABSTRACT

 

Coir is one of the strongest natural fibres extracted from coconut (Cocos nucifera L.) husk which is widely used all over the world for a variety of applications. Open retting is an ageold practice for the extraction of coir from coconut husks by placing them in natural water bodies. The pollution due to open retting practice accounts to biodegradable COD of 1.4 ton/ ton coir fibre and large quantities of nonbiodegradable polypehnols in the retting water bodies. This has been affecting natural heritage of rich biodiversity in the backwater bodies. The anaerobic degradation of the released organic pollutants results emission of the greenhouse gas, CH4, and H2S according to availability of sulphate in water. ‘Closed retting’ process eliminates all such pollution problem as well as produces quality fibre and coir pith. In this retting method biodegradable organics are converted to VFA fractions like acetic (71%), propionic (19%) and butyric acids (10%) and finally to CH4. The CH4 yield through closed retting for a ton of coir fibre is 490m3. There is no sulphide generation in this process as fresh water can be used for producing quality fibres. In this anaerobic process the oxidative polymerization and formation of coloured recalcitrant compounds are also prevented unlike in the open retting.

 

Keywords : Closed retting, Coir, Pollution, Polyphenols, Anaerobic Leach-bed

 

 

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